Stecca Pro 10|10

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Sent email to Steca, Germany as follows

Dear Sir/ Madam

On Thurs 6th November I bought, from Wind and Sun - one of your registered distributors, a Pro1010 controller, serial number 953154, to regulate the output of two 50 watt solar cells to a 100Ah battery.

I connected them yesterday around 2pm 8th November and noticed the draw on the battery, according to the inbuilt monitor, was 0.1A. As there was no load connected I thought the 0.1A which occasionally flashed to 0.2A was the units inability to process the low self consumption, rated in your manual as 0.0125A (12.5mA).

I was going to disconnect the unit from the battery overnight in case there was such a usage but decided to leave the battery connected.

This morning around 8am I checked the usage and found the total at 2Ah. As I have write this email at 10am it reads 3Ah. This, I reiterate, is with no load connected to the output terminals.

I assume the 1.2A is being dumped to heat whilst the 'load' seems to rise with Solar input; yet is still 0.1A at night. Could you please explain these readings as they are not what I would expect nor want?

Looking forward to your response.

Roger Lovejoy

P.S. I served in the Royal Navy as a Radio Electrician so I am familiar with a little more than basic electrical wiring.

4 comments

I arose at 4am on the morning of 10th Nov to read the Load Ah and the Steca records 5Ah. It is now nearly 10am and the reading is 6Ah. I suppose I can relay on the fact that the phantom use it consistent. Some 6Ah in 44hour (6000mA divided by 44 = 136mA) some 11 times the specified ‘own consumption’ of 12.5mA.

It begs the question; What is it measuring?

Clearly it is not measuring the load as I would expect.
Why would it measure it’s own consumption?
What happens to the waste power when the current is too much for the battery state? Is it measuring that?

It seems that although it is interesting, having some monitor, these questions make it a inaccurate in terms of power measurement.

I assume the Ah into the battery actually pass through the battery terminals. I say this as the Charge Ah is the same as the Load Ah, although I noticed during charging yesterday they did not keep pace and the Load Ah only caught up over night. I wonder if I disconnect the battery from the Stecca will it still show the Load Ah, but then obviously not as it will have no power, but I could try it in the day.???

So is this reading an un-understandable one or is it me that is failing to understand how the Steca works?

If you think this unit is faulty please send me another and I will install it and return the current one if that is the case. Of course as you didn’t sell me the unit directly maybe you could authorise Wind and Sun to send me one.

I wonder if you actually test the unit as I do? i.e. without any load for a significant time and if you do could you please sent me your data. Better still could you please send me the data anyway

All the best

Roger Lovejoy

12/11/14 @ 09:57
[b]Email Reply from Stecca[/b]

Dear Mr. Lovejoy,

the reason for the low consumption at the load connection of the charge controller are the components. If you load this connection you will see that in reality there are no consumption. You can also see this unreal consumption at the display of the charge controller because this value won’t be measured it would be calculated.

13/11/14 @ 10:14
Thank you for your prompt reply although it has not answered my queries, rather, it has provoked more thought and questions. I am not sure if part of the problem is language so I will take your responses one at a time.

First Sentence : ‘the reason for the low consumption at the load connection of the charge controller are the components.‘

You are saying there is a consumption but regard it as low and attribute it to ‘the components’

i) To qualify something as low there has to be a corresponding high and the only other figure I have, that you provide, is an internal ‘own consumption’ of 12.5mA. Clearly the consumption I am reading can only be qualified as high, by some 1000%.

ii) You say that the usage is due to ‘the components’; however how do you relate this ‘low consumption’ of some 3Ah a day to the specifications that ‘the components’ or self consumption is 12.5mAH (0.3Ah)

I cannot see why, if the rated self consumption is 0.3Ah per day I could be reading 3Ah per day. Clearly the screen output is either incorrect or the unit is using 3Ah per day. Either possibility is unacceptable.

Second Sentence : If you load this connection you will see that in reality there are no consumption.‘

I find this statement bizarre!

Presumably you mean connect a load to the Load terminals of the Steca and that somehow now I will not see any consumption.

So if no load is connected I will see a consumption, albeit questionable as to whether it is real or not, but if I do connect a load I will not see any consumption.

Maybe you mean I will not see the unreal consumption, only the real consumption, but how would I know what is real and what is not. The unit clearly shows some consumption.

Third Sentence : You can also see this unreal consumption at the display of the charge controller because this value won’t be measured it would be calculated.‘

i) Why does the fact that it is calculated and not measured mean that I can see an unreal consumption.

ii) Why would anyone want to see an unreal consumption?

ii) Why and how does the unit calculate a value from something that doesn’t exist?

All the best

Roger Lovejoy

P.S. For your information the ‘usage’ is consistent and after 4 days the reading is 12Ah

27/28 Dec 2017
During the evening of 27th power went off probably due to percentage charge going below ???. The charge had been at 43% so I thought it would be unlikely to have dropped to 30% which I think is the cut off level. When I went to check the level it was at zero and 11.6v.

Thus morning, the 28th, luckily there was a bit of sun and the percentage crept up to 6% after an hour or so and then jumped to 35%

November 10th, 2014
I arose at 4am on the morning of 10th Nov to read the Load Ah and the Steca records 5Ah. It is now nearly 10am and the reading is 6Ah. I suppose I can relay on the fact that the phantom use it consistent. Some 6Ah in 44hour (6000mA divided by 44 = 136mA) some 11 times the specified ‘own consumption’ of 12.5mA.

It begs the question; What is it measuring?

Clearly it is not measuring the load as I would expect.
Why would it measure it’s own consumption?
What happens to the waste power when the current is too much for the battery state? Is it measuring that?

It seems that although it is interesting, having some monitor, these questions make it a inaccurate in terms of power measurement.

I assume the Ah into the battery actually pass through the battery terminals. I say this as the Charge Ah is the same as the Load Ah, although I noticed during charging yesterday they did not keep pace and the Load Ah only caught up over night. I wonder if I disconnect the battery from the Steca will it still show the Load Ah, but then obviously not as it will have no power, but I could try it in the day.???

So is this reading an un-understandable one or is it me that is failing to understand how the Steca works?

If you think this unit is faulty please send me another and I will install it and return the current one if that is the case. Of course as you didn’t sell me the unit directly maybe you could authorise Wind and Sun to send me one.

I wonder if you actually test the unit as I do? i.e. without any load for a significant time and if you do could you please sent me your data. Better still could you please send me the data anyway